Phosphorus availability and microbial respiration across different tundra vegetation types
2012 (English)In: Biogeochemistry, ISSN 0168-2563, E-ISSN 1573-515X, Vol. 108, no 1-3, 429-445 p.Article in journal (Refereed) Published
Phosphorus (P) is an important nutrient in tundra ecosystems that co-limits or in some cases limits primary production. The availability of P is largely driven by soil characteristics, e.g., pH, organic carbon, and abundance of P-sorbing elements such as aluminium (Al) or iron (Fe). We tested how vegetation and soil properties relate to P availability across different tundra vegetation types. The different soil P fractions in the organic horizon were measured and plant foliar nitrogen (N) to P ratio and a plant bioassay was used as indicators of plant nutrient status. Microbial bioassays were used to study microbial respiration kinetics and in response to carbon, N, and P amendments. The distribution of P fractions differed significantly across vegetation types; labile fractions of P were less abundant in meadow sites compared to heath sites. Calcium-phosphates seemed to be an important P-fraction in meadows, but were only found in lower concentrations in the heath. There were only small differences in NaOH–extractable P between the vegetation types and this correlated with the distribution of oxalate-extractable Al. Plant N:P ratios and the plant bioassay indicated decreasing P availability from dry heath to mesic heath to mesic meadow. The microbial bioassay suggests that the heterotrophic microbial community is C-limited with N as a secondary limiting nutrient although there were indications that microbial P availability was lower in the meadow sites. Overall, we suggest that the observed variations in soil P across vegetation types are affecting both plant and microbial function although the differences seem to be relatively small.
Place, publisher, year, edition, pages
2012. Vol. 108, no 1-3, 429-445 p.
Phosphorus availability, Subarctic tundra, Hedley fractionation, Soil respiration, N:P ratio
IdentifiersURN: urn:nbn:se:umu:diva-46291DOI: 10.1007/s10533-011-9609-8OAI: oai:DiVA.org:umu-46291DiVA: diva2:437574